Soylent Green (1973)

Set in the overpopulated, polluted New York City of 2022, *Soylent Green* opens with what appears to be a routine murder investigation. In an overpopulated futuristic Earth, a New York police detective, Thorn (Charlton Heston), finds himself marked for murder by government agents when he gets too close to a bizarre state secret involving the origins of a revolutionary and needed new foodstuff. What starts as the simple case of a murdered corporate executive quickly spirals into a conspiracy that reaches the highest levels of a society on the brink of collapse, where the truth is the most dangerous commodity of all. *Soylent Green* earns its place among the best mystery movies by masterfully embedding a classic hardboiled detective story within its grim sci-fi vision. At its core, the film is a procedural; Thorn follows leads, questions witnesses, and uncovers clues in the classic noir tradition. The mystery brilliantly evolves from a simple "whodunit" into a far more profound and terrifying "what-is-it," as the central question shifts from the identity of a killer to the horrifying nature of the world's food supply. This culminates in one of cinema's most iconic and devastating reveals, a solution to the mystery that is not just a clever plot twist but a soul-crushing commentary, cementing the film as a masterclass in building an investigation toward an unforgettable conclusion.